The disclosure relates generally to displays, and more particularly, to organic light emitting diode (OLED) display apparatus and methods for making the same.
OLED, a self-light-emitting device, is emerging as a next-generation display because it does not require a backlight and has a high contrast, wide-viewing angle, fast response time, and low power consumption. The driving circuits of OLED display devices are usually fabricated on glass substrates using photolithography techniques. For conventional displays, such as television and mobile devices, low temperature polysilicon (LTPS) deposited on glass substrates is usually used as the channel material of thin file transistors (TFTs) in the driving circuits. Due to the limit of feature size for fabricating TFTs on glass substrates (e.g., the minimum line width is about 2-3 μm) and the relatively low mobility of LTPS, it is difficult to increase the pixel density of conventional displays, such as to more than 1,000 PPI for LTPS-based displays.
However, in some emerging technology areas, such as virtual reality (VR) and augmented reality (AR), displays with high pixel densities (e.g., above 2,000 PPI) and fast response time are desirable because the VR/AR headsets are close to human eyes and the pixels are usually enlarged by lenses. Thus, conventional liquid crystal displays (LCDs) and OLED displays using LTPS on glass substrates are not suitable for applications such as VR and AR. Accordingly, there exists a need for improved display apparatus and method for making the display apparatus to solve the above-mentioned problems.